1. Field of the Invention
This invention is concerning a new type of electromagnetic relay. Especially, it is concerning small electromagnetic relays whose internal resistance on the contact circuit side of an electromagnetic relay with the one-circuit three-contact gap has been reduced as much as possible and for which necessary improvements have been made to be able to allow the flow of large electric currents.
2. Description of the Related Art
First, we would like to explain about a conventional small electromagnetic relay 1 in accordance with FIG. 12. FIG. 12 is a vertical side view showing the outline of electromagnetic relay 1. The electromagnetic relay 1 shown therein consists of yoke 3 vertically installed on insulation base 2, which was mold-produced, Iron Core 4 which was fastened onto the Yoke 3, Coil 5, which was wound around a bobbin with iron core 4 being placed in the center, armature 6, which was installed to be able to revolve freely with the upper end of the armature 6 as the revolution supporting point, insulation card 7, which makes a piston move back and forth following the revolutionary move of the armature 6, moveable contact plate 8, whose lower end is fastened to the insulation base 2 and which makes revolutionary move back and forth due to the back and forth move of the insulation card 7 with the lower end as the revolution supporting point, moveable contact 9, which was installed on the moveable contact 8's upper end's outside surface, fixed contact plate 10, which was installed in front of and in parallel with the moveable contact plate 8, to contact with the front end of insulation card 7 and whose lowest end is fastened to the aforementioned insulation base 2 and which moves back and forth with that lowest end as the move supporting point, moveable contact 9, which was built on the outside of the upper end of moveable plate 8, fixed plate 10, which was build in front of and in parallel with moveable plate 8, fixed contact 11, which was installed on the backside of the upper end of fixed contact plate 10, facing the moveable contact 9, and cap 12, which accommodates all of the above.
This electromagnetic relay 1 is structured so that the iron core 4 attracts or releases one end of the armature 6 by means of electric on or off onto the coil 5, causing the armature 6 to revolve with the revolution supporting point of the armature 6 as the center, causing the lower end of the armature 6 to move the insulation card 7 back and forth, and that the back and forth move of the insulation card 7 causes the moveable contact plate 8 also to make revolutionary move back and forth with its lower end as the revolution supporting point, causing the moveable contact 9 installed on the moveable contact plate 8 to contact or leave the fixed contact 11 to make an open or close action between the moveable contact 9 and the fixed contact 11.
Meanwhile, as the moveable contact plate 8 has the structure of a cantilever spring whose lower end is fastened to the insulation base 2, this type of electromagnetic relays are used where required electric current capacity is not so large. (For example, refer to Patent Literature 1 to 3: Japanese Patent Application Laid-open Nos. H6-23166, H10-125202 and 2001-93393, respectively.)
In the case of conventional electromagnetic relays like this, the moveable contact plate 8 needs to be structured with a spring plate. For this reason, you cannot reduce the internal resistance on the contact circuit side, and if you are to use a moveable contact plate which has contact with the aim of reducing the internal resistance, you will have to use a thicker plate, a stronger spring and heavier moveable contact 9, which may cause such relays to malfunction when they receive some kind of shocks.